# US 11,910,552 B2 · Electronic devices with corrosion-resistant colored metal structures > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,910,552 B2 - Document ID: US11910552B2 - Status: Granted - Kind: B2 - Application number: 16/904,501 - Filed: 2020-06-17 - Published: 2021-12-23 - Granted: 2024-02-20 - Earliest claimed: 2020-06-17 - Assignees: Apple Inc. - Applicants: Apple Inc. - Inventors: Manish Mittal; Brian S. Tryon; James A. Yurko; Jing Zhou; Matthew S. Rogers; Naoto Matsuyuki - Web page: https://patentgrep.com/patent/US11910552B2 ## CPC - H05K 5/0243: {for decorative purposes} - C08K 3/08: Metals - H05K 5/0086: {portable, e.g. battery operated apparatus (casings for switching devices H01H9/02)} - H05K 5/0217: {Mechanical details of casings (covers, lids, hoods or members for covering apertures H05K5/03)} - H05K 5/04: Metal casings - C08K 2003/0831: {Gold} - H05K: PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS - C08K: Use of inorganic or non-macromolecular organic substances as compounding ingredients (paints, inks, varnishes, dyes, polishes, adhesives C09) ## Abstract An electronic device may have a housing. The device may include metal structures such as a metal member forming a portion of the housing, a portion of a strap, or other portions of the device. A gold-containing coating such as a layer of elemental gold or a gold alloy may cover the metal member to provide the metal member with a gold appearance or other desired appearance. To protect the metal member and the gold-containing coating, the metal member and gold-containing coating may be covered with a protective coating layer such as an organic protective layer. The organic protective layer may have a fluoropolymer layer with thiol coupling groups to promote adhesion to the gold-containing layer or may contain a polymer layer with silane and thiol coupling groups that serves as an adhesion promotion layer for an overlapping fluoropolymer layer with silane coupling groups. ## Claims ### Claim 1 An electronic device, comprising: electrical components; and a metal member coupled to the electrical components, wherein the metal member has an exterior surface covered with a coating and wherein the coating includes: a gold-containing layer that covers the exterior surface, and an organic protective layer that covers the gold-containing layer, wherein the organic protective layer comprises a fluoropolymer layer with silane coupling groups and a polymer layer with silane coupling groups and thiol coupling groups, wherein the polymer layer is interposed between the gold-containing layer and the fluoropolymer layer. ### Claim 2 (depends on 1) The electronic device defined in claim 1 wherein the thiol coupling groups of the polymer layer bond with the gold-containing layer. ### Claim 3 (depends on 2) The electronic device defined in claim 2 further comprising a metal adhesion layer between the exterior surface and the gold-containing layer. ### Claim 4 (depends on 3) The electronic device defined in claim 3 wherein the metal adhesion layer comprises a metal selected from the group consisting of chromium and titanium. ### Claim 5 (depends on 1) The electronic device defined in claim 1 further comprising a layer between the metal member and the gold-containing layer, wherein the layer between the metal member and gold-containing layer comprises an element selected from the group consisting of: titanium, chromium, carbon, nitrogen, silicon, and tantalum. ### Claim 6 (depends on 1) The electronic device defined in claim 1 wherein the gold-containing layer is a layer of gold. ### Claim 7 (depends on 1) The electronic device defined in claim 1 wherein the gold-containing layer is a gold alloy comprising an element selected from the group consisting of: platinum, palladium, and copper. ### Claim 8 (depends on 1) The electronic device defined in claim 1 wherein the silane coupling groups of the fluoropolymer layer are configured to bond to the silane coupling groups of the polymer layer. ### Claim 9 (depends on 8) The electronic device defined in claim 8 wherein the thiol coupling groups of the polymer layer are configured to bond to the gold-containing layer. ### Claim 10 (depends on 9) The electronic device defined in claim 9 further comprising a metal adhesion layer between the exterior surface and the gold-containing layer. ### Claim 11 (depends on 1) The electronic device defined in claim 1 wherein the metal member comprises a portion of a watch band, wherein the electronic device comprises a housing that encloses the electrical components, and wherein the watch band is coupled to the housing and the electrical components. ### Claim 12 (depends on 1) The electronic device defined in claim 1 wherein the metal member comprises a portion of a housing enclosing the electrical components. ### Claim 13 (depends on 12) The electronic device defined in claim 12 further comprising a display, wherein the housing has a front face and an opposing rear face, wherein the display is on the front face, and wherein the metal member is on the rear face. ### Claim 14 An electronic device, comprising: a display; a metal housing member coupled to the display; a watch band coupled to the metal housing member; a gold-containing layer on the watch band; a fluoropolymer with first silane coupling groups on the gold-containing layer; and a polymer layer with second silane coupling groups and thiol coupling groups, wherein the polymer layer forms an adhesion layer between the gold-containing layer and the fluoropolymer. ### Claim 15 (depends on 14) The electronic device defined in claim 14 wherein the gold-containing layer comprises a gold alloy bonded to the thiol coupling groups. ### Claim 16 (depends on 14) The electronic device defined in claim 14 wherein the gold-containing layer comprises a layer of gold bonded to the thiol coupling groups. ### Claim 17 An electronic device, comprising: a display; a metal housing member coupled to the display; a gold-containing layer on the metal housing member; a fluoropolymer layer with silane coupling groups; and a polymer layer with silane coupling groups and thiol coupling groups, wherein the polymer layer forms an adhesion layer between the gold-containing layer and the fluoropolymer layer. ### Claim 18 (depends on 17) The electronic device defined in claim 17 wherein the gold-containing layer comprises a gold alloy bonded to the thiol coupling groups and wherein the silane coupling groups of the fluoropolymer layer promote adhesion with the polymer layer. ### Claim 19 (depends on 17) The electronic device defined in claim 17 wherein the gold-containing layer comprises a layer of gold bonded to the thiol coupling groups and wherein the silane coupling groups of the fluoropolymer layer promote adhesion with the polymer layer.